A typical vehicle occupant protection system includes a crash sensor, such as an accelerometer, an inflatable air bag, and an actuation circuit that controls the actuation of the air bag in response to an output signal from the crash sensor. The actuation circuit includes a controller that evaluates the output signal from the crash sensor signal and provides an actuation signal when it determines that a vehicle crash event is occurring for which actuation of the air bag is desired.
Systems have been developed to control the amount of inflation of the air bag in response to a detected occupant position and/or occupant weight. Examples of this type of system are disclosed in U.S. Pat. No. 5,330,226 to Gentry et al., and U.S. Pat. No. 5,626,359 to Steffens, Jr. et al.